Had the same P13 and 14 fault codes on mine. The issue is the actuator solenoid not altering the cam position to the desired value. If you have FIAT MULTISCAN you can look at the desired and actual values whilst slowly revving the car, or better still, do a graph capture whilst driving. The values for both intake and exhaust desired and actual should be close. The duty cycle of the actuator is also shown, so you know when advance should happen.
The inlet solenoid is on the left hand side under the red engine cover and its the nearest one to you.
Costs about £80 from a FIAT dealer. Held in by two 10mm bolts. Pull out gently with a set of mole grips whilst turning. The exhaust and inlet solenoids are different parts.
Also check the cables to the connectors for damage, my wires were cracked slightly but not broken.
After replacement the check engine message will go away and the ECU will commence learning mode automatically as an emissions related engine part has been replaced.
My car was totally different afterwards, until another couple of 1000 miles, then I did an ECU reset and it runs well again. The Alfa ECU seems better when it knows less about the engine - Probably running high ignition advance whilst learning then gradually retards over time.
Don't replace your chain yet.